Black or White-An Inquiry Activity about Energy Absorption and Reflection

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Objective

Students will be able to describe which color absorbs more light and heat by participating in an investigation.

Big Idea

Black or white? Which color does a better job of keeping an ice cube from melting? The students will find out during this investigation.

Opening

5 minutes

This lesson was inspired by the lesson, A Place in the Shade.  In that lesson, students were given the challenge of designing a structure that would shade an ice cube and slow the melting process.  The materials provided for the activity include black and white construction paper.  The students did not make a connection between the color of paper used and the success of their structure.  I decided it would be fun to teach a lesson on absorption and reflection to see if the students could apply this information when they revise their structures in the lesson Still Looking for Shade.

Materials Needed:

  • 1 sheet of white construction paper per group
  • 1 sheet of black construction paper per group
  • 2 ice cubes, each in a zipper bag per group
  •  Black and White Recording Sheet included as a PDF with this lesson.

I begin the lesson by posing a question for the students.  I say, I am going to the beach and I want to bring a cup of ice water along.  I am wondering if it would be better to bring the ice water in a white cup or in a black cup.  I want you to talk in your group as to which one you think would do a better job and why.

I give the students time to talk.  When they are done, I invite different groups to share.  I make sure that they are telling "why" as I want to support them in communicating a clearly stated, evidence-based, compelling argument.  When they are done sharing, I ask them, How could we test to see if you are correct?  The students give some great ideas for how we could find out which color would do a better job.  We then move into the inquiry activity.

Investigation

20 minutes

I give each student a recording sheet.  I place a white piece of construction paper and a black piece of construction paper with an ice cube in a zipper bag on each on every work groups' table.  photo.  I say to the students, We are going to find out what which ice cube melts faster, the one on the black or the one on the white paper.  I want you to quickly draw picture of what each one looks like.  Then I want you to write down your prediction for which one you think will melt fist, the black or white one. 

I give the students time to record their predictions and record the baseline data.  When everyone is done, we take the black and white papers and the ice cubes and head outside.  We set the papers in a sunny spot and put the ice cubes on top of the papers.  We let it sit in the sun for about 10 minutes (I check on the ice a few times to monitor the melting progress).  When one cube is melted or nearly melted, we go back outside and check our results.  The students bring their recording sheets with clipboards.  They record the results of our experiment.  After everyone has recorded the results, we go back inside to discuss what happened.

Discussion

10 minutes

To guide our discussion, I ask the students the following questions:

  • What happened to the ice cube on the white paper? 
  • How about the one on the black paper?
  • Why do you think that happened?
  • If you were going outside on a hot day, what color clothing would be the best to wear?  Why?
  • What if you were going outside on a cold day?  Why?

 

I want the students to make the connection that the white paper reflects the sun's energy and the black paper absorbs the suns energy.  I actually use those terms, but scaffold them for the students, by giving a "kid friendly" definition along with the terminology.  I say, the black paper absorbs or soaks in the suns energy, just like a sponge soaks up water.  The white paper reflects, or shines back the suns energy, kind of like shining a flashlight on a mirror.

I discuss the students' findings with them individually when I check their recording sheet to check for understanding.  See video

After our discussion, we move into the lesson closing.

Closing

5 minutes

I want my students to be able to apply what they learned during today's lesson to a real life situation, so I have them partner up with a neighbor and I ask them this question:

My friend and I went to the beach on a very hot day.  My friend was wearing said he was really hot and not feeling well.  He was wearing a black t-shirt and hat.  How could I have helped my friend? 

I give the students time to discuss the scenario.  It is my hope that the students will apply what they learned about colors during their discussion.  If not, I will remind them of what happened to the ice cube on the black paper.